Boris Johnson and Rishi Sunak will both be given fixed penalty notices by police for parties hosted during lockdown.
No10 confirmed the prime minister and chancellor will both receive fines for attending events held while the nation stayed at home.
Downing Street confirmed the penalty notice given to the prime minister was for a birthday party held for him on June 19, 2020.
Both faced calls to quit from Nicola Sturgeon and Keir Starmer.
But Scottish Tory leader Douglas Ross stood by his party leader and said he should remain in his job due to the war in Ukraine, despite previously demanding his resignation.
He said: “The public are rightly furious at what happened in Downing Street during the pandemic.
“However, as I’ve made very clear, in the middle of war in Europe, when Vladimir Putin is committing war crimes and the UK is Ukraine’s biggest ally, as President Zelensky said at the weekend, it wouldn’t be right to remove the Prime Minister at this time.
“It would destabilise the UK Government when we need to be united in the face of Russian aggression and the murdering of innocent Ukrainians.”
It also emerged that Carrie Johnson, the prime minister’s wife, would be fined by police for breaking lockdown.
The Met Police confirmed today they had issued at least 30 more fines for gatherings at Downing Street and Whitehall.
It means more than 50 fixed penalties have now been handed out since officers first began their investigation.
A No 10 spokeswoman said: “The Prime Minister and Chancellor of the Exchequer have today received notification that the Metropolitan police intend to issue them with fixed penalty notices.
“We have no further details, but we will update you again when we do.”
Boris Johnson initially denied late last year that any lockdown rules had been broken by senior Tories and government workers while restrictions were in place.
But it later emerged the PM had hosted a Downing Street garden party and attended his birthday bash.
Police confirmed in January they were investigating 12 events which had reportedly breached Covid laws.
One included a Westminster party – which the prime minister did not go to – held by staff the night before Prince Philip’s funeral.
‘Boris Johnson must resign’
Nicola Sturgeon said: “Boris Johnson must resign. He broke the law and repeatedly lied to parliament about it.
“The basic values of integrity and decency – essential to the proper working of any parliamentary democracy – demand that he go. And he should take his out of touch chancellor with him.”
Keir Starmer said: “Boris Johnson and Rishi Sunak have broken the law and repeatedly lied to the British public. They must both resign.
“The Conservatives are totally unfit to govern. Britain deserves better.”
SNP Westminster leader Ian Blackford said Boris Johnson’s position was “completely untenable”.
He wrote: “Boris Johnson misled parliament, lied to the public and broke the law. He must resign or be removed from office.
“There simply cannot be one rule for the Tories and another for the rest of us.”
Boris Johnson also faced furious calls to go from his own backbenches after the damaging revelations he had broken lockdown first emerged.
For the chancellor, the fine comes after it emerged his wife had not been paying UK taxes on overseas income due to her non-dom status.
Mr Sunak also came under pressure as it emerged he held a US green card until recently.